1. Field of the Invention
The present invention relates to a body panel assembly and a method for making a body panel assembly.
2. Background Art
Body panels are used as external surfaces on automotive and aerospace vehicles. Automotive body panels are commonly made from stamped sheet metal. These body panels are heavy, expensive, and have poor stiffness. Aerospace body panels may consist of aluminum or titanium reinforcement spars that are riveted to an outer carbon fiber layer to provide structural support. External carbon fiber surfaces are undesirable in many applications since they have rough surfaces that require extensive surface preparation prior to painting or coating. In addition, carbon fiber panels cannot be readily repaired to fix surface defects such as dents.
According to the present invention, a body panel assembly having an inner panel and an outer panel is provided. The inner panel has a first surface and a second surface opposite the first surface. The inner panel may be a non-metallic material, such as a carbon fiber reinforced polymer. The outer panel may have an internal surface and an external surface opposite the internal surface. The outer panel may be a metallic material, such as aluminum, and may have a greater coefficient of thermal expansion than the inner panel. An adhesive may be disposed between the inner panel and the outer panel to join the panels and inhibit galvanic corrosion. A portion of the outer panel may be hemmed to the inner panel to join the inner and outer panels together. The outer panel may have a first coating layer applied to the internal and external surfaces. A second coating layer may be applied to the first coating layer around the radius of the hem.
A scrim pad may be disposed between the inner panel and the outer panel along the first surface and/or an end surface to inhibit galvanic corrosion. The scrim pad may be attached to the second surface of the inner panel with an adhesive or molded in place.
According to another aspect of the invention, a duct portion may be disposed between the inner panel and the outer panel for transporting ambient air through the body panel assembly. The body panel assembly may also include a wheel well formed by a portion of the inner panel as well as fender and decklid portions formed by the outer panel.
According to another aspect of the invention, a method for making a body panel assembly for a vehicle is provided. First, an inner panel is fabricated with a first predetermined shape. Next, an outer panel is fabricated with a second predetermined shape. An adhesive may be applied to the first surface or the internal surface. The outer panel is then positioned in contact with the adhesive and the first surface of the inner panel. Finally, a portion of the outer panel is hemmed to the inner panel to provide a smooth edge.
The step of fabricating the outer panel may be conducted using a superplastic forming process and may also include coating the outer panel after it has been formed into the second predetermined shape. The step of fabricating the inner panel may include molding in a scrim pad. Alternatively, the scrim pad may be attached to the inner panel when the adhesive is applied to the inner panel.